A motor stator typically includes a laminated electrical steel structure with slots to allow the insertion of conductive windings, typically made from enameled copper wire. As the stator steel is quite conductive itself, an insulating material is typically added as a lining to the stator slots to prevent electrical current flowing between the copper winding and the steel stator. The material might typically be a sheet of polyester film, such as Mylar® produced by Dupont Teijin Films, perhaps in a sandwich structure with other materials such as Dacron® produced by Invista Technologies. This material must be formed in such a way as to electrically isolate the winding from the stator. In most cases, the material is also bent back over itself at the ends (or “cuffed”) in order to ensure that a minimum air clearance between copper and steel is met. The copper windings are also typically held in place with thicker Mylar® wedges which are driven into the tops of the slots once the copper is inserted. The “end turn” portion of the copper winding which protrudes from the stator is held in place by tying it with string.
A typical example of this prior art stator arrangement is shown, in part, in FIG. 1 of the accompanying drawings. In this example, a motor stator 1 includes a laminated stator core 3 and winding coils 5 wound about teeth of the stator core 3. The winding coils 5 are electrically isolated from the stator core 3 by a layer of insulating material 7. This material is formed with cuffs 9 at each end of the stator core teeth so as to maintain integrity of the electrical isolation.
The “wiring rules” (for example AS60335.1 for household appliance motors in Australia) specify that a certain minimum clearance distance be maintained between the surface of the “uninsulated” copper wire and the surface of the steel stator core (the wiring rules do not count the usual enameled coating on the copper wire as insulation). Thus, in this example, a clearance distance 11 is provided to establish this minimum required distance between the “uninsulated” copper wire surface and the steel stator core surface.
This means that the coils of the winding 5 are longer than they actually need to be—the wire goes straight through the slot and continues in a straight line through the cuffed portion 9 of the insulator 7 before turning over into another slot of the stator core 3. The coils of the winding 5 are thus enlarged to make sure the minimum clearance requirement can be met.
Some disadvantages of this conventional winding/insulation arrangement are as follows:                It is complicated. Each slot must have a well positioned slot liner (possibly with cuffed ends) and a slot wedge. Typically, the windings would also be “tied in” to the stator with string to hold them in place.        It is difficult to achieve a good result. Processes must be tightly controlled; issues such as single wires slipping under the insulation, the wedges not properly retaining the winding and the cuffs not correctly locating the winding within the allowed clearance can occur.        The winding process is expensive due to the number of process steps and checking that must occur.        Some winding material is included unnecessarily, at the cost of motor efficiency, due to the additional material required to meet the minimum clearance requirement.        
With the foregoing in mind, there remains a need for an insulation arrangement for axial flux machines which is more convenient, facilitates assembly, reduces waste and improves efficiency of electrical machines compared to prior art arrangements.